In a Long Term Evolution (LTE) system, nodes at the network side are generally connected over wired links, that is, eNBs are connected over wired links, and the eNBs and core network nodes (e.g., a Mobility Management Entity (MME), a Serving Gateway (S-GW), etc.) are also connected over wired links, as illustrated in FIG. 1.
Alike in an architecture with a radio relay node, legacy eNBs are also connected over wired links, and the eNBs and core network nodes are also connected over wired links; and the relay node and a Donor eNB (DeNB) serving the relay node communicate via a wireless interface, as illustrated in FIG. 2.
In future development of a mobile communication system, as there are growing transmission rates and capacities as demanded by users for radio broadband services, one of working means to improve the capacity and the throughput of a network is ultra-dense deployment of access nodes to better satisfy the demand of the users. As can be expected, more access nodes will be sure to be introduced in an area with a significant throughput demand in the future to thereby greatly increase the density of deployment in a cell. Each small cell covers only a small area in which the users proximate to each other can be provided with high transmission efficiency. On the other hand, in order to better address the issues of interference coordination between the different small cells, and mobility of the users, the small cell need to have some dependency upon a macro cell covering a large area, that is, there is an interface required between the small cells and the macro cell to transmit control signaling and even user data.
If the small cells are deployed densely, then wired backhaul links (i.e., links between the small cells and the network) may not be deployed in all the scenarios, so wireless backhaul links will be also a typical scenario for the sake of convenient deployment, and convenient of the nomadic access nodes. In such a scenario, the small cells need to communicate with the network side nodes and/or a macro station covering a large area via a wireless interface.
In the prior art, if there is a small cell to be connected with a network over a wireless path, then the small cell will generally communicate wirelessly with a macro station directly. However in a common scenario, for example, where there is a long distance between the small cell and the macro station, there is a shielding obstacle between the small cell and the macro station, etc., there may be such a poor quality of a radio channel between the small cell and the macro station that if the small cell communicates wirelessly with the macro station directly, then there may be low transmission efficiency, and a significant transmission delay.